UHA L
OW
P
ROFILE
U
NIT
H
EATER
I
NSTALLATION
O
PERATION
AND
S
ERVICE
M
ANUAL
6
SECTION 3: CRITICAL CONSIDERATIONS
3.1 Basic Information
UHA[X][S] heaters have automatic ignition burners
for ON/OFF operation only.
3.2 Manufactured Units
Gas-fired, power-vented unit heater with tubular heat
exchanger. Units shall have a minimum of 82%
thermal efficiency. The standard unit shall consist of
a non-separated combustion design with an
aluminized heat exchanger. Design and heat
exchanger alternatives shall be offered as follows:
• Separated Combustion: A separated combustion
unit shall consist of an enclosed sealed burner
box to which combustion air is vented through a
piece of internal flexible air duct. This duct
terminates at an exterior cabinet flange to which
a vent ran to the outside of the heated space
should be attached.
• Stainless Steel Heat Exchanger: A stainless
steel heat exchanger unit shall consist of heat
exchanger tubes, heat exchanger tube supports,
heat exchanger tube plates and a vent box
produced of 409 stainless steel.
3.3 Location and Suspension
All models:
• Must be installed indoors.
• Must be installed in a level position with
horizontal discharge.
• May be mounted on a shelf of non-combustible
material using shelf mounting brackets.(
See
Page 11, Figure 6
and Page 12, Figure 7
for
details.)
• May be suspended from above (
See Page 11,
Figure 5
) or from wall brackets of sufficient
strength to support the heater as listed in the
Dimension Data Table
on Page 49, Section 15.1
.
Drop rods must be a minimum of 3/8" diameter
mild steel. Four suspension points (3/8" nuts)
are located on top of the heater.
• Must be installed in a manner which allows
access to all serviceable components.
See Page 7, Figure 4
for details.
3.4 Minimum Required Installation Clearances
Clearances around the heater and vent must be as
indicated
on Page 7, Figure 4
;
Page 17, Figure 9
through Page 20, Figure 14
to ensure access for
servicing, and correct operation.
3.5 Clearances to Combustibles
Clearances must be as indicated
on Page 7, Figure
4
. If clearances to combustibles are not indicated,
then installation clearances apply.
3.6 Ventilation
It is important to ensure that there is adequate air
space around the heater to supply air for
combustion, ventilation and distribution in
accordance with local and national code
on Page
14, Section 6
.
WARNING
Fire Hazard
Some objects can catch fire or explode
when placed close to heater.
Keep all flammable objects, li
q
uids and
vapors the re
q
uired clearances to
combustibles away from heater.
Failure to follow these instructions can
result in death, injury or property dama
g
e.
WARNING
Carbon Monoxide Hazard
Heaters may be installed
vented or unvented.
Vented heaters must be
vented outdoors.
Unvented heaters must be
installed in buildin
g
s with
ventilation rates as per
section 6.4.
Failure to follow these
instructions can result in
death or injury.
